Expandable sealants are known in this art such as described in U.S. Pat. Nos. 4,427,481; 4,874,650; 5,266,133; 5,373,027; 5,506,025; 5,266,133; 5,373,027; and 5,678,826; and European Patent No. EP 0 730 998B1; the disclosure of each of which is hereby incorporated by reference. One conventional cavity sealing arrangement and method is described in U.S. Pat. No. 5,040,803; the disclosure of which is also hereby incorporated by reference. Other convention cavity sealants comprise polyvinyl chloride (PVC) based materials that are pumped into location and, in some cases, expand after being exposed to a sufficient amount of heat. Conventional sealants also include polyurethane based or containing foams. Typically, these sealants are employed in automotive applications for filing cavities, stiffening adjacent components and dampening sound/vibrations.
Conventional sealant compositions may be limited in their application due to the temperature and time required to cause the sealant to expand. Certain conventional compositions also require the addition of heat to produce the expandable composition as well as to cause the composition to expand. There is a need in this art for an expandable composition that: 1) is activated at a relatively low temperature, 2) adheres to a metal substrate, 3) is easily installed and remains in a predetermined location and 4) for some applications is resistant to fuel, e.g., diesel and gasoline.